Sewing machine

Abstract

Disclosure relates to sewing machine capable of preventing thread cutting or deterioration caused by interference between leading end of needle and upper thread, that includes: head frame; needle bar supported on head frame to be movable up and down; needle having needle hole that penetrates in transverse direction with respect to axial line and has upper thread inserted thereinto and be coupled to lower end of needle bar to move up and down between lowered stitching position and lifted needle position; and presser foot unit having pressing part that is provided with needle guide hole through which needle passes and moves up and down between downward pressing height position where pressing part presses sewing material and lifting release height position where pressing part is lifted and spaced apart from sewing material and pressing foot arm that supports pressing part.

1 . A sewing machine, comprising:
 a head frame;   a needle bar configured to be supported on the head frame to be movable up and down;   a needle configured to have a needle hole that penetrates in a transverse direction with respect to an axial line and has an upper thread inserted thereinto and be coupled to a lower end of the needle bar to move up and down between a lowered stitching position and a lifted needle position; and   a presser foot unit configured to:
 have a pressing part that is provided with a needle guide hole through which the needle passes, and moves up and down between a downward pressing height position where the pressing part presses a sewing material and a lifting release height position where the pressing part is lifted and spaced apart from the sewing material, and a pressing foot arm that supports the pressing part, and 
 dispose the pressing part at a normal horizontal position so that the needle passes through the needle guide hole when the pressing part is at the downward pressing height position, and horizontally move the pressing part from the normal horizontal position to an excursion horizontal position spaced by a predetermined horizontal excursion amount so that the upper thread passing through the needle hole does not interfere with a leading end of the needle when the pressing part is at the lifting release height position. 
   
     
     
         2 . The sewing machine of  claim 1 , wherein the presser foot arm supports the pressing part to enable the pressing part to perform an excursion movement and a return movement between the normal horizontal position and the excursion horizontal position, and
 further including an excursion driver configured to apply an excursion acting force to the presser foot arm to cause the pressing part to perform at least one of the excursion movement and the return movement.   
     
     
         3 . The sewing machine of  claim 2 , wherein the excursion driver includes an excursion profile part whose lateral protrusion height gradually changes along an elevating direction on the presser foot arm , and a contact action member that contacts the excursion profile part to apply the excursion acting force. 
     
     
         4 . The sewing machine of  claim 3 , wherein the contact action member has a rolling contact part. 
     
     
         5 . The sewing machine of  claim 2 , wherein the excursion driver includes an excursion cam roller that rotates in contact with side surface of the presser foot arm and applies the excursion acting force to the presser foot arm, and a roller driver that rotatably drives the excursion cam roller by interlocking with an elevating movement of the presser foot arm. 
     
     
         6 . The sewing machine of  claim 2 , further comprising:
 a reaction elastic member configured to apply an elastic force to the presser foot arm in a direction opposite to the excursion acting force.